Macroscopic activity states in brain networks mediate cognition and
behavior. Pathological changes in these network dynamics are associated
with both neurological and psychiatric disorders. Studying how cellular
elements give rise to activity dynamics represents a promising approach
to understanding and eventually treating disorders of the central
nervous system. Here, we introduce large-scale simulations of neuronal
networks to study (1) how network topology gives rise to network
dynamics and (2) how brain stimulation can be used to modulate and
enhance macroscopic network dynamics. We demonstrate that global weak
perturbations of neuronal signaling is a powerful brain stimulation
approach and show experimental results from animal electrophysiology and
a human trial that demonstrate the feasibility of this novel brain
stimulation paradigm based on transcranial current stimulation.